• [转]Android ListView异步加载图片


    本文转自:http://www.cnblogs.com/stay/articles/1900012.html

    package cn.riddles.activity;
      
    import android.app.Activity;
    import android.os.Bundle;
    import android.widget.ListView;
      
    public class MainActivity extends Activity {
        private ListView lv;
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            lv = (ListView) this.findViewById(R.id.test_lv);
            lv.setAdapter(new SongListAdapter(this));
        }
    }

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    package cn.riddles.activity;
      
    import android.content.Context;
    import android.util.Log;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.ImageView;
    import android.widget.TextView;
    /**
     * @author riddlezhang 歌曲条目适配器
     */
    public class SongListAdapter extends BaseAdapter {
        private static final String TAG = "SongListAdapter";
        private Context mContext;
        private String[] strings = {"王力宏","吴尊","何润东","金城武","吴彦祖"};
        public SongListAdapter(Context mContext) {
            this.mContext = mContext;
        }
      
        public void setmContext(Context mContext) {
            this.mContext = mContext;
        }
      
        public int getCount() {
            return paths.length;
        }
      
        public Object getItem(int position) {
            return position;
        }
      
        public long getItemId(int position) {
            return position;
        }
      
        public View getView(int position, View convertView, ViewGroup parent) {
            convertView = LayoutInflater.from(mContext).inflate(R.layout.lv_adapter, null);
            ImageView image = (ImageView) convertView.findViewById(R.id.image);
            TextView songer = (TextView) convertView.findViewById(R.id.songer);
            image.setTag(paths[position]);
            songer.setText(strings[position]);
            new CanvasImageTask().execute(image);//异步加载图片
            Log.i(TAG, "execute:"+strings[position]);
            return convertView;
        }
          
    }
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    <DIV class=cnblogs_Highlighter><PRE class=brush:java;gutter:false;>package cn.riddles.activity;
      
    import java.io.InputStream;
    import java.lang.ref.SoftReference;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import java.util.HashMap;
      
    import android.content.Context;
    import android.graphics.drawable.Drawable;
    import android.os.AsyncTask;
    import android.util.Log;
    import android.view.View;
    import android.webkit.URLUtil;
      
    /**
     * @author riddlezhang 异步加载图片
     */
    public class AsyncViewTask extends AsyncTask<View, Void, Drawable> {
        private View mView;
        private HashMap<String, SoftReference<Drawable>> imageCache;
      
        public AsyncViewTask(Context mContext, String mobileinfo) {
            imageCache = new HashMap<String, SoftReference<Drawable>>();
        }
      
        protected Drawable doInBackground(View... views) {
            Drawable drawable = null;
            View view = views[0];
            if (view.getTag() != null) {
                if (imageCache.containsKey(view.getTag())) {
                    SoftReference<Drawable> cache = imageCache.get(view.getTag().toString());
                    drawable = cache.get();
                    if (drawable != null) {
                        return drawable;
                    }
                }
                try {
                    if (URLUtil.isHttpUrl(view.getTag().toString())) {// 如果为网络地址。则连接url下载图片
                        URL url = new URL(view.getTag().toString());
                        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                        conn.setDoInput(true);
                        conn.connect();
                        InputStream stream = conn.getInputStream();
                        drawable = Drawable.createFromStream(stream, "src");
                        stream.close();
                    } else {// 如果为本地数据,直接解析
                        drawable = Drawable.createFromPath(view.getTag().toString());
                    }
                } catch (Exception e) {
                    Log.v("img", e.getMessage());
                    return null;
                }
            }
            this.mView = view;
            return drawable;
        }
      
        protected void onPostExecute(Drawable drawable) {
            if (drawable != null) {
                this.mView.setBackgroundDrawable(drawable);
                this.mView = null;
            }
        }
      
    }
    </PRE>
    </DIV>
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  • 原文地址:https://www.cnblogs.com/freeliver54/p/2545062.html
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